extmod/modutimeq: Copy of current moduheapq with timeq support for refactoring.

extmod/modutimeq.c

+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/nlr.h"
+#include "py/objlist.h"
+#include "py/runtime0.h"
+#include "py/runtime.h"
+#include "py/smallint.h"
+
+#if MICROPY_PY_UHEAPQ
+
+#define MODULO MICROPY_PY_UTIME_TICKS_PERIOD
+
+// the algorithm here is modelled on CPython's heapq.py
+
+STATIC mp_obj_list_t *get_heap(mp_obj_t heap_in) {
+    if (!MP_OBJ_IS_TYPE(heap_in, &mp_type_list)) {
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "heap must be a list"));
+    }
+    return MP_OBJ_TO_PTR(heap_in);
+}
+
+STATIC bool time_less_than(mp_obj_t item, mp_obj_t parent) {
+    if (!MP_OBJ_IS_TYPE(item, &mp_type_tuple) || !MP_OBJ_IS_TYPE(parent, &mp_type_tuple)) {
+        mp_raise_TypeError("");
+    }
+    mp_obj_tuple_t *item_p = MP_OBJ_TO_PTR(item);
+    mp_obj_tuple_t *parent_p = MP_OBJ_TO_PTR(parent);
+    mp_uint_t item_tm = MP_OBJ_SMALL_INT_VALUE(item_p->items[0]);
+    mp_uint_t parent_tm = MP_OBJ_SMALL_INT_VALUE(parent_p->items[0]);
+    mp_uint_t res = parent_tm - item_tm;
+    if ((mp_int_t)res < 0) {
+        res += MODULO;
+    }
+    return res < (MODULO / 2);
+}
+
+STATIC void heap_siftdown(mp_obj_list_t *heap, mp_uint_t start_pos, mp_uint_t pos, bool timecmp) {
+    mp_obj_t item = heap->items[pos];
+    while (pos > start_pos) {
+        mp_uint_t parent_pos = (pos - 1) >> 1;
+        mp_obj_t parent = heap->items[parent_pos];
+        bool lessthan;
+        if (MP_UNLIKELY(timecmp)) {
+            lessthan = time_less_than(item, parent);
+        } else {
+            lessthan = (mp_binary_op(MP_BINARY_OP_LESS, item, parent) == mp_const_true);
+        }
+        if (lessthan) {
+            heap->items[pos] = parent;
+            pos = parent_pos;
+        } else {
+            break;
+        }
+    }
+    heap->items[pos] = item;
+}
+
+STATIC void heap_siftup(mp_obj_list_t *heap, mp_uint_t pos, bool timecmp) {
+    mp_uint_t start_pos = pos;
+    mp_uint_t end_pos = heap->len;
+    mp_obj_t item = heap->items[pos];
+    for (mp_uint_t child_pos = 2 * pos + 1; child_pos < end_pos; child_pos = 2 * pos + 1) {
+        // choose right child if it's <= left child
+        if (child_pos + 1 < end_pos) {
+            bool lessthan;
+            if (MP_UNLIKELY(timecmp)) {
+                lessthan = time_less_than(heap->items[child_pos], heap->items[child_pos + 1]);
+            } else {
+                lessthan = (mp_binary_op(MP_BINARY_OP_LESS, heap->items[child_pos], heap->items[child_pos + 1]) == mp_const_true);
+            }
+            if (!lessthan) {
+                child_pos += 1;
+            }
+        }
+        // bubble up the smaller child
+        heap->items[pos] = heap->items[child_pos];
+        pos = child_pos;
+    }
+    heap->items[pos] = item;
+    heap_siftdown(heap, start_pos, pos, timecmp);
+}
+
+STATIC mp_obj_t mod_utimeq_heappush(size_t n_args, const mp_obj_t *args) {
+    mp_obj_t heap_in = args[0];
+    mp_obj_list_t *heap = get_heap(heap_in);
+    mp_obj_list_append(heap_in, args[1]);
+    bool is_timeq = (n_args > 2 && args[2] == mp_const_true);
+    heap_siftdown(heap, 0, heap->len - 1, is_timeq);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_utimeq_heappush_obj, 2, 3, mod_utimeq_heappush);
+
+STATIC mp_obj_t mod_utimeq_heappop(size_t n_args, const mp_obj_t *args) {
+    mp_obj_t heap_in = args[0];
+    mp_obj_list_t *heap = get_heap(heap_in);
+    if (heap->len == 0) {
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_IndexError, "empty heap"));
+    }
+    mp_obj_t item = heap->items[0];
+    heap->len -= 1;
+    heap->items[0] = heap->items[heap->len];
+    heap->items[heap->len] = MP_OBJ_NULL; // so we don't retain a pointer
+    if (heap->len) {
+        bool is_timeq = (n_args > 1 && args[1] == mp_const_true);
+        heap_siftup(heap, 0, is_timeq);
+    }
+    return item;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_utimeq_heappop_obj, 1, 2, mod_utimeq_heappop);
+
+STATIC mp_obj_t mod_utimeq_heapify(mp_obj_t heap_in) {
+    mp_obj_list_t *heap = get_heap(heap_in);
+    for (mp_uint_t i = heap->len / 2; i > 0;) {
+        heap_siftup(heap, --i, false);
+    }
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_utimeq_heapify_obj, mod_utimeq_heapify);
+
+STATIC const mp_rom_map_elem_t mp_module_utimeq_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_utimeq) },
+    { MP_ROM_QSTR(MP_QSTR_heappush), MP_ROM_PTR(&mod_utimeq_heappush_obj) },
+    { MP_ROM_QSTR(MP_QSTR_heappop), MP_ROM_PTR(&mod_utimeq_heappop_obj) },
+    { MP_ROM_QSTR(MP_QSTR_heapify), MP_ROM_PTR(&mod_utimeq_heapify_obj) },
+};
+
+STATIC MP_DEFINE_CONST_DICT(mp_module_utimeq_globals, mp_module_utimeq_globals_table);
+
+const mp_obj_module_t mp_module_utimeq = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&mp_module_utimeq_globals,
+};
+
+#endif //MICROPY_PY_UHEAPQ